JohnMo

They all have them, but some also look at crankcase temperature as a permission to start the compressor. It may not have an error code for it. We are also well insulated and ran the heat pump mostly in the E7 cheap period, but even then used a lot more than expected although very cheap energy. This year I am doing straight WC and compare. Our WC curve is something like 26 @ 10 OAT and 31 @ -5 to see how it goes. With Cosy I would just reduce target temp a couple of degrees during expensive period. And maybe uplift target during really cheap periods. Get your WC curve right it will modulate itself well.

The cost tariff but confuses me are you saying at -10 you only run the heat pump for a couple of hours? If you are only running on a set tariff period I would check your programmes to check what's occurring. If your system has cooled to sub zero temperature it will take hours to recover. That's why it's pump cold water around. Things to check crankcase heaters, if the crankcase isn't warm no start. In sub zero temps don't switch it to standby or off. Cosy isn't really designed for heat pumps (heat pumps and battery yes) running for short bursts is no use .

Daft thing with all these reports they miss one fundamental If we and others had not installed PV or wind (expect the same sort of paper on wind), the grid would not be decarbonised and we would still be reliant on coal etc. So the end state of reports like this is in 2030/2050 if we are net zero or close to it, is no renewable energy source makes sense. It should only be compared against say a carbon emitter, which is what it is displacing, not a mix of other non carbon emitters. Normal for this type of report it's sh#te in, sh#te out. Maybe it was written by or for the Telegraph, they seem to love this sort of thing.

Even without room stats or any radiator valves the following happens. WC flow temp is closely matched to heat loss, adding just enough energy toto keep up with overall heat loss. The boiler is doing a couple of things to manage flow temp, trying to stay to target flow temperature and maintain a fixed delta between flow and return. So steady state it just ticks away. Start your fire, the follow occurs 1. Room temp and eventually house temp goes up. 2. The delta between room and radiator or UFH decreases, so heat output reduces 3. Return temp to boiler is higher 4. Boiler modulates the output to return the dT between flow and return. 5. As things get warmer the boiler cycles off. 6. Boiler circulation pump continues, as fire goes off and room cool, boiler will cycle back on. So you have a flow temperature target of 30 degs. The boiler will have a hysterisis around the 30 degs to help stop cycling to much. So say 5 degs above and below. So it allows the flow temperature to go up to say 35 and then it stops the heating cycle, when the flow temperature gets down to 25 it starts it's heat cycle again. Remember the boiler is also managing the flow return delta. So your room temp goes up because the sun's out or your fire is on. As water flows through a radiator it gives off heat and has an expected dT say 5 degs. Water goes in at 30 and out at 25 normally. If the room gets hotter from your fire, the radiator cannot give it's heat off as easily so the dT reduces to 3. Now boiler will slow it's self down and add less energy to get it's delta back in to equilibrium. The above only occurs well on a low temperature system, if your expected flow temp are above 50. You will need to think about TRVs on most radiators (not all). But you don't want ones that will just go open or closed you want modulating ones. This is what my boiler manual says on the subject.

I would first fix everything, then building control can inspect. Then do plasterboard and second fix on a room by room basis. But you would have no electricity until second fix was finished for the electric in most rooms. Plumbing could be sorted using a manifold for hot and cold. You just need an isolator for each wet room and then branch distribution within the room.

Just test against it's pressure flow curve. At full speed and closed head (zero flow) it should produce around 5 Bar (check your curve for exact pressure or head). If your making close to 5 Bar your connected correctly and achieving full speed

Also found this in their technical guide. This requirement may be driving the additional CU so the heat pump can have a Type B RCD and the rest of the house etc a Type A.

Removal of insulation is to be frank a daft idea. Making the ceiling vaulted may add to the issue, as you have more trapped hot air. We use - keep the sun out with blinds first. Then - Opening windows and doors to get cross ventilation. We are also in a bungalow I see no issue opening windows, when you home. Cooling is also used.

Excellent result. Different world in Scotland we had 23 our hottest day.

Just read this and then looked at my install, it has type B MCB and Type A RCDs. So I need to upgrade to type B RCD I believe. https://professional-electrician.com/technical/18th-edition-rcd-requirements-for-heat-pump-installations-doepke/

Basically you can use roof breathable membrane on either wall or roof, but you can only wall breathable membrane for walls (not suitable for a roof). Wall specific is a lower spec overall. You need to be specific here, are you talking breathable or non-breathable?

Mine (Maxa) says "recommended to install a type B differential switch, the installation of a different type switch could give rise to untimely trips." Vaillant instructions states (section 7.3) "To protect people, type B universal-current-sensitive residal-current circuit breakers must be used if these are stipulated for the installation site." So pretty consistent.

Go on to Google play and download CDM Wizard and do all your construction phase risk assessments. Print them out, keep on site and issue to contractors.

You made a point that on the first run you only made 1.2 and then added a pressure vessel and then got 2 bar. You seemed surprised, so was only commenting why it was the case and so other reader that have no clue about pump curves could follow. Also suspect looking at the pump curve for your pump you were measuring dynamic pressure not static. Or running at slow speed.

Possibly if it doesn't comply with regs.

Pump run on pressure and volumetric flow curve. The more flow the lower the head developed. If you are running out of an unrestricted pipe it will never develop much head. So for example the Jet 62, produces around 16m head (approx 1.6 bar) at full flow and 40m head or 4 bar against a closed discharge.

Not that sure it makes any difference. By the time most houses have had a couple of coats of emulsion the building structure is pretty much separated from the internal environment (except for air leakage, which comes from inside or most likely outside). So MVHR or no ventilation the structure needs to perform on its own merits. The mould and fug come from two things, cold bridging and/or poor ventilation. Not really related to a rotten structural frame.

You think so and are lead to believe that, but it's not exactly true. Our house has MVHR and our heated summer house dMEV. Both have a sound ventilation strategy. As an example mid winter humidity on 16 Jan House Summer house Both are heated to a similar temperature, and the humidity is at a similar figure, with the dMEV slightly lower.

I would have the CU inside the house, then just a single incomer. Use a hockey stick tube and then easy to seal at floor level. Then take power to the garage with a single cable to a dedicated CU for the garage.

Ace thanks

I need to run a cable about 6m from the ASHP Modbus outlet to a controller. Anyone know what cable I need, and where I can buy by the metre?

Ask the ICF suppliers, your structural engineer doesn't need to be on your doorstep.

As said above do it once, go straight to heat pump. Q Not sure if your heating requirements but a 4 to 6kW Panasonic monobloc doing heat to ground floor UFH only. You need Cylinder with 3m² coil Diverter valve Heat pump UFH with 1.5 storey, do 150 to 200mm centres. Run all from a single manifold, no mixer no pump, no actuators. No thermostat needed either. Set to run weather compensation and then let it get on with it. It will self control itself, without intervention. I now have a single thermostat but use it to switch between heating and cooling only. Don't bother going MCS either, it's not worth the hassle and the rip off factor. Shop around you can do it £7k + cheaper ASHP £2k, cylinder £1k. Getting a combi to work is hard work Read up some of the steps I took getting the heat pump to run how I wanted it too. Miss out the hard work.

With Durisol you can do all underground buildup with that if you want. You remove the insulation and full fill with concrete.

Wouldn't expect so. You just need to ensure you have lots of insulation under it. About 150mm of PIR, anything less you will paying to heat up the outside world.